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Yes one needs to maintain the single master cylinder very well. See second part of this short thread. You are one poorly molded or deteriorated seal away from total brake failure & fluid returning to the reservoir instead of pressurising brakes. Many replacement end of piston seals provided from UK vendors are fractionally too thin to seal the inlet port. I have machined my piston to accommodate this. A Jaguar OE seal did not give me reliable brakes.
Forewarned is forearmed ~ read from "Another issue we had....." ~ I find it irritating that a simple Jaguar original replacement part could cause this. At least the bore seal is likely to leak slightly long before failure.
You are right on that. I did the same as you did, I replaced all of the lines with new hard lines, used stainless lines, and replaced every brake part from master, servo, etc. because I wanted everything new and change the brake fluid regularly as I do not like having a single master. The quality of the Fooseway calipers are very nice & high quality but it would be great if someone designed a dual master upgrade kit. I do drive the crap out of my car but I service it very regularly and check everything often as this is the only car I have that has a single master.
Yes ~ all of my braking system is new ~ pipework (Cunifer), servo, stainless braided flexibles (Goodridge), calipers & master cylinder stainless lined to spec etc. As my car is not upgraded other than that I drive it carefully. I don't like single circuit brakes & you can't depend on Jaguar handbrakes. My handbrake works very well by old Jag standards as everything is new but I would not trust it to do anything worthwhile in a brake failure situation. Old Dunlop calipers & pad area are a bit of a joke by modern standards.
Yes ~ all of my braking system is new ~ pipework (Cunifer), servo, stainless braided flexibles (Goodridge), calipers & master cylinder stainless lined to spec etc. As my car is not upgraded other than that I drive it carefully. I don't like single circuit brakes & you can't depend on Jaguar handbrakes. My handbrake works very well by old Jag standards as everything is new but I would not trust it to do anything worthwhile in a brake failure situation. Old Dunlop calipers & pad area are a bit of a joke by modern standards.
Would you ever upgrade the calipers to something like the 4 piston Fosseway 4 pistons & rotors or you set on keeping it stock? I agree, as I went with all new and eliminated the stock calipers with the much better quality Fosseyway calipers and rotors. Do you have any mileage recommendations to prematurely replace the master and servo to be on the safe side, as I am curious to your thoughts on that?
No ~ I want to keep it stock for shows right down to correct Cadmium plated (looking) Dunlop calipers. I'm quite happy to drive it accordingly ~ it's not my daily driver. Brake fluid I would change every 2 years religiously. I stainless lined all master, slave cylinders & calipers on the car as I knew it would be a low mileage vehicle that stands a lot. The servo is not that critical as it is likely to show issues with lumpy braking or hard pedal long before a failure & unlikely you will ever lose brakes. Might have to push a lot harder on the pedal to stop the car. About 4 times harder. Most areas are likely to show weeping before failure & dropping fluid level in the reservoir over & above the normal pad wear drop. The master cylinder is the weak spot. To be on the very safe side I'm going to rebuild my master cylinder every 5 years or 50K miles. I will never do 50K miles so every 5 years I will do an elastomer change in the master cylinder.
I know this is very cautious. We never know the source of many rubber products & quality varies vastly so I'm basing this on seal swell & other accelerated testing of durability done in our labs. (oilco)
I don't want to ever see this. We don't know if brakes played a part ~ the car left the road & went down a gully & the front subframe tore loose from it's mountings. Driver survived (or I would not show the pics) ~ Many broken bones, feet, legs & spinal damage.
Last edited by Glyn M Ruck; Sep 25, 2020 at 08:20 AM.
I always found the Dunlop system on my Mk2 to work very well in terms of stopping power and I don't remember problems of fade. However, the wear rate of pads, especially the front ones, discs and cylinders was horrendous. And the handbrake wasn't something to be taken seriously. As a consequence, replacing the whole system is part of my rebuild plan. I've made no decisions yet, but my research is leading me to Fosseway or XJS/series 3 XJ based system. The final choice may depend on how much I'm ready to spend at that stage
Regarding the failure of rubber seals, I have the impression that they don't last long if exposed to air after being immersed for a long time in hydraulic fluid for a long period. I don't have any scientific basis for this. But I've had a few rubber seals give up shortly after other work where the clutch or brake systems may have been drained.
As I use my car stopping power is fine & I've never suffered fade. Primaz with his V8 modded monster does some serious canyon runs at high speed & his brakes just fell over from what he's told us. I have yet to assess pad life. First set of pads.
Glyn, I used to change my front pads every year. Don't be tempted to let them get too thin as they spread and can become difficult to extract from the caliper. As stoppers, I always had confidence in them. They had a good, hard pedal feel and never gave me a problem in the Alps or Appennines.
Regarding rubber seals you might well be onto something there. We have seen a number of fluid and temperature exposed seals actually split. A bit of a worry & of course original source unknown. "Rubber" is a bit of a black art. We provide base oil dewaxing extracts to a number of rubber plants. If it is Michelin you know the end product is going to be thoroughly tested. If it's some small operation churning out basic seals, rubber bushings etc. you don't know what you are getting.
The radiator mounting bushes provided by Barratts had split on my car within 3 months of fitting. Had to change them again.
Excuse picture quality. I've blown up a small portion of a much larger pic.
Last edited by Glyn M Ruck; Sep 25, 2020 at 08:53 PM.
Glyn, I used to change my front pads every year. Don't be tempted to let them get too thin as they spread and can become difficult to extract from the caliper. As stoppers, I always had confidence in them. They had a good, hard pedal feel and never gave me a problem in the Alps or Appennines.
Thanks for the tip. Will do. I always keep spares.
